A comprehensive phenotypic and genotypic evaluation of Spanish groundnuts from diverse crosses to identify superior and stable donors for fresh seed dormancy

Breeding high yielding groundnut cultivars with 2–3 weeks of fresh seed dormancy, particularly in Spanish-type cultivars, enhances the sustainability of agriculture in groundnuts. In this context, we conducted a comprehensive phenotypic and genotypic evaluation of advanced breeding lines developed in the genetic background of Spanish types. By employing multi-phenotyping and marker data, we identified PBS 15044, 16004, 16013, 16015, 16016, 16017, 16020, 16021, 16026, 16031, 16035, 16037, 16038, 16039, 16041, and 16042 with 2–3 weeks dormancy (> 90%).The various parametric and non-parametric estimates identified the stable fresh dormant genotypes with one or more superior economic trait. PBS 16021, 15044, 16038, and 16039 identified with high hundred pod weight (HPW) were also reported having high intensity of dormancy (> 90% for up to 3 weeks); PBS 15044, 16016, PBS 16038 and PBS 16039 with high hundred kernel weight (HKW) also reported with up to 3 weeks fresh seed dormancy; and PBS 16013, 16031, and 16038 with up to 3 weeks fresh seed dormancy had high shelling percentage (SP). They can be used to develop lines with the desired level of dormancy, and high yields, by designing appropriate breeding strategies.


Plant materials and experimental site
A comprehensive evaluation was conducted on 29 advanced breeding lines (ABLs) of groundnut developed from diverse crosses followed by selection at advanced stage (Table S1) along with three released dormant check varieties viz., Girnar 3, Dh 86 and TPG 41 at ICAR-Directorate of Groundnut Research (DGR), Junagadh, Gujarat, India in a medium black calcareous (12% CaCO 3 ), clayey, Ustochrept soil.Test materials were sourced from our own gene bank at ICAR-Directorate of Groundnut Research, Junagadh.The test materials used in the present study are numbered and used with same nomenclature throughout the manuscript.All the plant material was obtained and developed at ICAR-DGR, Junagadh and no specific permissions are required as they are our own advanced breeding lines developed from crossing at ICAR-DGR.The experiment was arranged in a randomized complete block design (RCBD) with three replications.Each accession was planted in a single row of 3 m in length, with a spacing of 60 cm between rows × 10 cm between plants.Geographically, the experimental site is located at 21 o 31' N latitude, 70 o 36' N longitude at an altitude of 63 m above mean sea level comprising black calcareous soil.Proper crop management practices, such as the application of a recommended dose of fertilizers (50-40-25 kg NPK/ha) were complied.

Phenotyping protocols and parameter estimated for fresh seed dormancy
The genotypes were evaluated for fresh seed dormancy for three seasons viz., Kharif 2021(kh21), summer-2022 (sum22) and Kharif 2022 (kh22), by testing them under (i) field testing, (ii) laboratory conditions and (iii) genotyping using allele specific marker associated with fresh seed dormancy, the fresh dormant ABLs were genotyped on a validation panel comprising a GMFSD-1, an allele specific marker for fresh seed dormancy as described by Kumar et al. 2019  10 .For Kharif (kh) experiment, the seeding process occurred during the first two weeks of July, while the harvesting activities were conducted during the first two weeks of November.Whilst, for summer (sum) experiment, the seeding process occurred during the first two weeks of February, and the harvesting activities were conducted during the first week of June.For, (i) field test, seeds from freshly harvested pods of groundnut were treated with carbendazim (3 g/kg of seed) and sown in randomized complete block design with three replications.Each genotype was planted in a single row of 3 m in length, with a spacing of 60 cm between rows and 10 cm between plants (Fig. 1a, b).For, (ii) laboratory screening, standard operating procedure (SOP) for germination test was followed as proposed by Janila et al. (2018)(Fig.1c) 11 .The freshly harvested seeds from each genotype were treated with fungicide, treated seeds were placed in petriplate and watered regularly.The data on number of seeds germinated were recorded at weekly interval for up to 21 days to calculate intensity of dormancy (IOD) as described by Gangadhara et al. 2022 (intensity of dormancy 15 days after sowing in the field (IOD15F), 21 days after sowing in the field (IOD21F), 15 days after sowing in petriplate (IOD15L), 21 days after sowing in petriplate (IOD21L) 8 .For field germination tests moisture was maintained in the soil at field capacity throughout the experiment.The genotypes for germination tests were harvested at maturity as indicated by blackening of inner parenchyma of the pod 12 .To study fresh seed dormancy, a sample of mature pods were randomly selected and shelled immediately after harvesting and precaution was taken to prevent any damage of the testa, cotyledons and embryo while removing seeds from pods.Freshly harvested mature seeds were used for phenotyping.The mean pod moisture content of summer harvested produce was 38% and Kharif season harvested pods had 32% moisture content.

Evaluation of fresh dormant advanced breeding lines (ABLs) for yield and its components
The set of 29 Spanish bunch advanced breeding lines of groundnut that were screened for FSD were also evaluated for yield (pod yield per plant; PYLP) and its component traits (direct and positively contributing traits with yield) such as hundred pod weight (HPW), hundred kernel weight (HKW) and shelling percentage (SP) in grams for three seasons namely, Kharif 2020, Kharif 2021, and summer 2022.Standard agricultural practices and plant

Statistical analysis
The data analysis was performed using version 4.2.1 of the R statistical software 13 .The data on intensity of dormancy (IOD), yield and yield-related variables were analysed using a combined analysis of variance (ANOVA) to evaluate the existence of genotype by season interaction (GSI).All the data underwent log transformation for normalisation prior to analysis.In order to facilitate AMMI biplot modelling, each year and location was considered as a distinct and autonomous environment and were analysed using packages "agricolae". .Homogeneity of error mean squares as revealed by Levene's (Levene, 1960) test (p = 0.85) provided the statistical validity to pool the data from all seasons to perform AMMI analysis 14 .AMMI analysis was undertaken to detect and characterize genotype × season interaction (GSI) 15 .The signal rich component of GSI (GSI Signal ) sum of squares was computed as GSISS noise-GSI Noise , where GSI noise = GSI degrees of freedom × error mean squares from the AMMI ANOVA 16 .

Estimation of yield relative to the environmental maximum (YREM) of genotypes
The mean value relative to the environmental (season in our study) maximum (YREM) 17 .was computed as Y ij = X ij /MAX j , where Y ij and X ij are the YREM and mean value, respectively, of genotype 'i' and season 'j' .MAX j is the maximum value for any 'genotype' observed in season j .YREM was estimated using MS excel software.YREM is a special type of standardized estimate of genotype's performance with nullified year main effect.We performed one way ANOVA based on BLUP and YREM estimates to estimate the significance/otherwise of differences among fresh dormant advanced breeding lines.

Estimation of statistics to assess stability of genotypes differing in performance
The AMMI-based stability parameters (ASTABs), such as ASI were computed 18 .The formula was derived from an AMMI Stability Index (ASI), as originally proposed by Jambhulkar et al. 2014 18 .Although AMMI can be considered the best tools for simultaneously visualizing the mean grain yield and genotype stability, these cannot provide the exact numerical information required for comparison.Therefore, biplots alone cannot be relied on where more than two PCs are required to interpret a considerable proportion of GSI.The stability parameters in this study, namely, AMMI stability index (ASI) utilize all significant PCs for their estimation and were also considered for calculating simultaneous selection index (SSI).
Simultaneous stability index (SSI) incorporate mean yield and stability index in a single equation and is calculated as: SSI = rASI + rY where, rASI is the rank of ASI value and rY is the rank of mean yield of genotype across environments.The AMMI and stability indices were determined using R statistical software, version 3.4.1 13.The genotypes with lower and higher average ASI-and SSI-based ranks were interpreted to exhibit high and low performing genotypes, respectively.

Handling plant materials and methods
The collection and handling of plant and methods were in accordance with all the relevant guidelines.

Intensity of dormancy
Mean performance and ANOVA A comprehensive analysis was performed in order to dissect the main effects and assess the interrelationships within and between the factors of variation.The study revealed significant genotypic differences for IOD (15F, 21F, 15L and 21L) within each season (Table S2).The present study also revealed the existence of significant genotype × season interaction differences for the IOD tested under different germination tests.Consequently, higher estimates of broad-sense heritability were also observed for IOD in each season that depicts the higher proportion of phenotypic variation contributed due to genetic values.The genotypic accuracy of selection (As), which measures the correlation between predicted and observed values were recorded from 0.98 to 1.00.In addition coefficient of variation (CV) ranged from 5.61 to 18.21 (Table S2).The mean values of IOD15 in the field ranged from 72.36 (sum22) to 81.09 (kh21); IOD21F ranged from 67.81 (kh22) to 73.49 (kh21); IOD15L ranged from 69.86 (sum22) to 77.92 (kh22) and IOD 21L ranged from 65.59 (sum22) to 66.77 (kh22) (Table S3).S3).In the present study, the results showed that around 17 breeding lines had more than 90% mean intensity of dormancy from both field and laboratory germination tests for 2 weeks.Among these, 16 breeding lines had cumulative IOD more than 90% for upto 3 weeks after sowing.

The validation of fresh seed dormant groundnuts with allele-specific markers associated with fresh seed dormancy
The validation of fresh dormant genotypes via marker-assisted screening in addition to phenotypic screening was also performed in this study to identify accessions with 2-3 weeks of dormancy.So, these 29 ABLs phenotyped for germination percentage were also genotyped with allele specific marker GMFSD1 to validate the dormancy.GMFSD1 is an allele specific marker (B05_111598196) developed from the chromosome B05, through QTL-Seq analysis 10 .In the present study, this marker showed clear polymorphism between dormant (> 80% IOD, 21 DAS) and non-dormant parents (< 10% IOD, 21DAS) and co-segregated with the dormant phenotype equivalent or www.nature.com/scientificreports/more than 80 percent intensity of dormancy (Fig. 1d).The marker exhibited remarkable efficiency in distinguishing between nondormant and dormant genotypes of Spanish types.However, there were a few exceptions wherein the marker data were not in accordance with the phenotyping data.In the validation panel, except genotypes, PBS 16020, 16021, 16024, 16026, 16027, 16042, 16044, 16052, and 16053 all other ABLs along with checks showed positive band with marker GMFSD1.Among these, only genotypes, PBS 16027, 16044, and 16052 were non-dormant (< 20% IOD at 3 weeks after sowing) in germination tests under field and laboratory conditions.Other genotypes though dormant in phenotyping tests showed negative results in genotyping panel.Further, PBS 16025, 16028, 16029, and 16032, though reported non-dormant (< 20% IOD at 3 weeks after sowing) from phenotyping test showed positive amplification in validation panel.

AMMI-stability analysis for fresh seed dormancy
The mean genotypic values from three different seasons were subjected to AMMI ANOVA analysis.AMMI ANOVA indicates a larger contribution of sum of squares (SS) attributable to additive genotype main effects for fresh seed dormancy (88.36% to 94.46%) (Table 1).Further, mean squares (MS) attributable to main effects of genotypes (GEN), seasons (ENV) and multiplicative GSI effects (ENV: GEN) were significant for IOD (except non-significant environment effects for IOD21L).The variance caused by GSI was further subdivided into variance caused by signal and noise (Table 2).Partitioning GSI into signal and noise portions indicated that the signal portion was higher (54.39-93.27%)than the noise portion (6.73-45.61%)for FSD.Hence, AMMI analysis is appropriate for data sets where-in SS due to GSI Signal are at least as large as those due to additive genotype main effects 16 .www.nature.com/scientificreports/

AMMI biplot analysis
The AMMI stability showing the relationship between experimental genotypes and test environments for fresh seed dormancy (IOD15F, IOD15L, IOD21F and IOD21L) across three seasons is presented in Fig. 2a-d.The season kh21 was farthest from biplot origin, with long vectors representing strong interaction forces, while kh22 and sum22 were nearer to the origin and had shorter vectors with weak interaction forces for IOD15F, IOD21L, IOD21L, while for IOD15L, kh22 with long vector represented strong interaction forces 19

Comparative performance and stability of genotypes differing in intensity of dormancy as assessed by AMMI based stability index
The visualization of AMMI1 biplots was difficult since 32 genotypes were studied with many of them overlapping, creating a fuzzy figure, so AMMI stability index was computed.The variety with the lowest AMMI stability Index (ASI) calculated from the IPCA axis and IPCA scores is the most stable 20,21 3).

Identification of stable and productive genotypes by BLUP
The presence of a significant G × S interaction suggests that one genotype's yield may be superior to another genotype in one environment but inferior in another, implying that BLUP analysis is necessary 23 .From BLUP estimates, PBS 15044, 16004, 16013, 16015, 16016, 16017, 16020, 16021, 16026, 16031, 16035, 16037, 16038, 16039, 16041, 16042, 16045, TPG 41 and Girnar 3 had the highest predicted means above grand mean among the tested genotypes for IOD15DAS with no considerable differences among them.The same set of genotypes also had the highest predicted means among the tested genotypes for IOD 21DAS (Fig. 3a-d).

Comparative performance of genotypes differing in intensity of dormancy as assessed by YREM
YREM is an indicative of magnitude of crossover GSI.Therefore, in the absence of crossover GSI, the average YREM of a genotype tested across seasons (Kharif and summer) must be 1.0.Any departure of YREM of a www.nature.com/scientificreports/genotype from 1.0 is attributable to loss in its attainable mean performance due to crossover GSI 17 .For example, if a genotype has an average of 0.90 across-seasons YREM, then 10% of its attainable performance is lost due to crossover GSI.In our study, PBS 16004, 16015, 16021, and 16041 with an average YREM of 1.0 were highly stable with zero cross over interactions and PBS 16016, 16017, 16020, 16026, 16031, 16037, 16038, 16039, with an average YREM value of 0.98-0.99 were stable for intensity of dormancy 15 days after sowing.Similarly, PBS 16015, and 16041 with YREM of 1.0 were highly stable; and PBS 16004, 16016, 16017, 16021, and 16031 were comparatively stable more intensity of dormancy 21 days after sowing based on cumulative results of field and laboratory germination tests (Table 4).

Mean vs stability for fresh seed dormancy
A joint interpretation of individual trait performance and stability of genotypes across the seasons is presented in the four quadrants of Y × WAASB biplot in Fig. 4a-d.The genotypes or environments (seasons) placed in quadrant I are unstable or environments with high discrimination ability and low productivity below the grand mean.In quadrant II, the productivity of the genotype is above the grand mean but unstable.The environments in quadrant II were good discriminating environments with high magnitudes of the response variable.Genotypes in quadrant III have low productivity but stable due to the lower values of WAASB.The environments in quadrant III is considered poorly productive and with low discrimination ability.The genotypes in quadrant IV are highly productive and broadly adapted due to the high magnitude of the response variable and high stability performance.The present study includes the seasons, sum22 and kh22 in quadrant I, followed by kh21 in quadrant II of the WAASB biplot for fresh seed dormancy.This indicates that all three seasons were good discriminating environments for fresh seed dormancy.The season sum22 is unfavorable and less productive with the high discriminating ability for the studied trait and is placed in quadrant I. PBS 16024 (IOD15F); PBS 16039 and 16053 (IOD21F); PBS 16035 (IOD21L) are genotypes places in quadrant II, indicating high mean but variable performance.These genotypes displayed superior performance in either of the seasons, but not all.Genotypes in quadrant III have low productivity but stable due to the lower values of WAASB such as, PBS  All the remaining genotypes are included in quadrant IV of WAASB biplot.These genotypes are highly stable, but at the cost of their comparatively poor performance.This group is relevant in means that these genotypes had consistently superior trait values across seasons.1).

Yield and related attributes
In contrast for PYLP, analysis observed the greater contribution of environments (46%) followed by genotypic effects (21.34%) and 16.81% of the total variation was explained through interaction effects.The variance caused by GEI was further subdivided into variance caused by signal and noise.Consequently, for yield and related attributes signal portion was higher (51.70-69.37%)than the noise portion (30.63-48.30%)(Table 2).Further, www.nature.com/scientificreports/ the significant contribution of genotypes and GSI Signal to total variation among the genotypes across seasons, for yield and related traits, justify the application of AMMI and BLUP models to our data to understand patterns of GSI.The multiplicative component of AMMI models consists of the singular value/multiplication factor of IPCA, the genotype eigenvector, and the environment eigenvector 24 .In the present study, the first PCs explained 68% (HKW) to 87% (PYLP) of GSI, indicating that most variation was captured by the first component, whereas second component accounted for 12.60 to 31.80 percent of the GSI, indicating a significant contribution of environment on genotype and trait expression performance.

AMMI1 biplot analysis for yield and attributes
The AMMI stability showing the relationship between experimental genotypes and test environments for PYLP, HPW, HKW and SP across three seasons is presented in Fig. 5a-d.For PYLP, HPW, HKW and SP, sum22; kh20 and kh21; kh20; and kh21 respectively, showed weak interaction forces.The genotypes, PBS 16028, PBS 16032, PBS 16046, and PBS 16053 for PYLP (Fig. 5a); PBS 16021, PBS 16032, PBS 16039, and PBS 16044 for HPW (Fig. 5b); PBS 16016, PBS 16032, PBS 16038, and PBS 16039 for HKW (Fig. 5c); and PBS 16038, PBS 16032 and Dh 86 for SP (Fig. 5d) were superior performing.Out of these genotypes, PBS16028 for PYLP; PBS 16021 and PBS 16039 for HPW, PBS 16016 and PBS 16032 for HKW, and PBS 16038 and Dh 86 for SP was placed on zero PC1 scoreline, or closer to PC1 line, making it more stable with wider adaptation to the test environments.PBS 16032 though had highest HPW, but was found to be unstable specifically adapted to the test environment.
Similarly, PBS 16038 had specific adaptation to the test environment for HKW.5).Simultaneous selection indices (SSI) for genotypes were calculated using the sum of ASI ranks and genotype ranks determined from pod yield and related traits   the grand means as determined by BLUP analysis.Further, among these genotypes PBS 16021, 15044, 16038, and 16039 identified with high HPW were documented to possess a significant degree of dormancy (greater than 90% for duration of 3 weeks).Subsequently, genotypes of high HKW such as PBS 15044, 16016, PBS 16038, and PBS 16039, and with high SP viz., PBS 16013, 16031, and 16038, had fresh seed dormancy for a maximum of 3 weeks.

Discussion
Groundnut (Arachis hypogaea L.) is a food legume that is cultivated on a global scale.It is renowned for its substantial protein and unsaturated oil content.However, one of the most significant constraints impeding its production is the in situ sprouting of Spanish groundnuts.Genotypes with over 90% dormancy and 2-3-weeks duration are more successful in regions where precipitation patterns during crop maturity are unpredictable 3 .A study conducted to assess seed dormancy in a U.S. groundnut mini-core collection revealed notable variability among the accessions in terms of fresh seed germination % 25 .The extent to which a plant goes into dormancy (IOD) is mostly determined by its genes, although environmental conditions are also important 26 .The high percentage sum of squares attributable to the "Genotype" factor in the current investigation indicated that genetic variation among genotypes contributed substantially to the observed differences in the IOD.The examination of the Spanish-type groundnut ABLs for dormancy intensity in the field and laboratory and other yield characteristics across multiple seasons unveiled notable variations in the G × S interaction 27 .The presence of an interaction effect implies that the germination percentage exhibits seasonal variation, potentially attributable to non-genetic variables including temperature, precipitation, humidity, solar radiation, and environmental factors.The development of these advanced breeding lines involved the design of varied crosses including dormant genotypes, namely the advanced line or Virginia type (sub spp.hypogaea var.hypogaea), as one of the parental lines.The results presented in this study align with the findings reported by Kumar et al. (1991) and Kumar et al.
(2017), they also observed notable genetic variability in the degree of dormancy.Nevertheless, the significant www.nature.com/scientificreports/ In the present study, AMMI1 is studied due to its higher predicative accuracy attributable to (i) capture signal rich component of GSI and (ii) adjust mean estimates of genotypes closer to their true values 16,33 .The estimates of YREM, is an intuitive, and genotypes attendance-independent measure of test genotype's performance 17 .YREM is a dynamic measure of genotypes' performance, as it varies with the performance of best genotypes in a given environment and the best genotype also varies with the environment.The breeding value of genotypes is represented by BLUP, which is a preferred method for predicting the overall performance of genotypes.AMMI biplot analysis, along with BLUP, can be employed to uncover yield performance and stability in various seasons.This enables the selection of genotypes with wide or particular adaptation, depending on breeding requirements.Yield by environmental PC1 and yield by WAASB from AMMI, can be can be taken into account for this objective.AMMI model, followed by ASI and SSI stability models, AMMI 1 biplots, and BLUP identified the stable genotypes with one more superior economic trait.PBS 16021, 15044, 16038, and 16039 with > 90% dormancy for up to 3 weeks identified with high HPW; PBS 15044, 16016, PBS 16038 and PBS 16039 up to 3 weeks FSD had high HKW; and PBS 16013, 16031, and 16038 with high SP in the genetic background of dormant lines.It is possible to make use of these identified ABLs in order to develop novel peanut varieties that have specified levels of fresh seed dormancy and high yields/other traits by employing appropriate breeding strategies.

Conclusion
In order to reduce the amount of in situ germination losses that are caused by unexpected rains during harvest or delayed harvesting, it is essential to have a brief period of seed dormancy, which typically lasts between 2 and 3 weeks, particularly in the Spanish bunch type.The identified accessions, which have a dormancy period of two to three weeks and are superior in one or more economic traits, show promise for the breeding of commercial groundnut cultivars that are resistant to pre-harvest sprouting.This would help to reduce losses that are caused by untimely rainfall.The current work not only brought attention to the significance of seed dormancy, but it also brought attention to the possibility of the stable ABLs that were identified for targeted breeding programmes that aim to improve resistance to pre-harvest sprouting in commercially cultivated varieties.

Figure 1 .
Figure 1.Phenotyping variation for fresh seed dormancy (a,b) Field germination tests of fresh and mature kernels from freshly harvested pods.(c) Laboratory germination tests in petriplate.(d) Advanced Breeding Lines validated on a validation panel comprising a marker GMFSD-1, an allele specific marker for fresh seed dormancy 10 .

Table 2 .
Estimates of sum of squares due to signals and noises by using AMMI model in groundnut.GSI, genotype × season interaction.Vol:.(1234567890)Scientific Reports | (2024) 14:14988 | https://doi.org/10.1038/s41598-024-64681-6 22nce, ASI give an idea about only the stability of genotypes and does not provide any information about mean performance so, simultaneous selection index (SSI) was computed22by adding the ranks of stability parameter and mean performance.The least SSI is considered as most stable with high mean values, whereas high SSI is considered as least stable with low means22.Based, on cumulative results of field and laboratory conditions, for IOD 15 days after sowing, PBS 16015, 16021, 16041 and 16045 were most desirable based on SSI.While, for IOD 21 days after sowing based on cumulative results, PBS 16015, 16016, and 16041 was most desirable (Table Vol.:(0123456789) Scientific Reports | (2024) 14:14988 | https://doi.org/10.1038/s41598-024-64681-6www.nature.com/scientificreports/

Table 3 .
Comparative ranks of AMMI stability index (ASI) and simultaneous selection index (SSI) for intensity of dormancy in groundnut.IOD15F intensity of dormancy 15 days after sowing (field), IOD21F intensity of dormancy 21 days after sowing (field), IOD15L intensity of dormancy 15 days after sowing (laboratory), IOD21L intensity of dormancy 21 days after sowing, laboratory, rY ranks based on mean performance, rASI ranks based on AMMI stability index, SSI simultaneous selection index.

Table 4 .
Estimates of YREM's of groundnut genotypes for intensity of dormancy.IOD15F intensity of dormancy 15 days after sowing (field), IOD21F intensity of dormancy 21 days after sowing (field), IOD15L intensity of dormancy 15 days after sowing (laboratory), IOD21L intensity of dormancy 21 days after sowing, laboratory.

Overall identification of superior genotypes for yield and related traits in the genetic back- ground of fresh seed dormancy
From, the cumulative analysis superior performing genotypes viz., PBS 16004, 16015, 16021, 16037 and 16041 (IOD15DAS); PBS 16015, 16016, 16021, and 16041 (IOD21DAS) were stable throughout the screening seasons.PBS 16028, 16032, 16046, and 16053, which were among the highest-performing genotypes for PYLP, also exhibited stability in AMMI1 biplot and YREM analysis.Further, PBS 16021, 16032, and 16039 for HPW; PBS 16016, 16032, 16038, and 16039 for HKW; and 16038 and 16032 for SP were superior in terms of performance and stability.Among these, PBS 16028 (PYLP); PBS 16021, 16039 (HPW); PBS 16016 (HKW), and 16038 (SP) showed superiority from SSI analysis.The predicted means for each of the genotypes mentioned were also greater than

Table 5 .
Comparative ranks of AMMI stability index (ASI) and simultaneous selection index (SSI) for yield and related traits in groundnut.PYLP pod yield/plant, HPW hundred pod weight, HKW hundred kernel weight, SP shelling percentage.